This invention relates to a process of preparing an O-alkyl-N-cyanoacetimidate useful as an intermediate of pharmaceuticals and agricultural chemicals. In particular, this invention relates to, in preparing an O-alkyl-N-cyanoacetimidate by reaction of an orthoacetic acid ester with cyanamide, a process of preparing an O-alkyl-N-cyanoacetimidate which comprises making the start of the reaction in the presence of an alkaline catalyst.
As to a process of preparing an O-alkyl-N-cyanoacetimidate by reaction of an orthoacetic acid ester with cyanamide, some processes have hitherto been known, and for example, Journal of Organic Chemistry, volume 28(1963), page 1816 discloses a process of preparing an O-alkyl-N-cyanoimidate by carrying out the above reaction in the presence of 2 moles of acetic anhydride. In this reaction, as shown in the following reaction equation (1), orthoacetic acid triethyl ester reacts with cyanamide to form O-ethyl-N-cyanoacetimidate and corresponding 2 moles of ethanol, and this ethanol reacts with acetic anhydride to form 2 moles of acetic acid and 2 moles of acetic acid ethyl ester. 
However, this process could not be said to be a suitable process in putting into practice on an industrial scale because separation of the by-products and isolation of the product are difficult.
In U.S. Pat. No. 4,956,503 (DE 3,815,084) is proposed, as shown in the following reaction equation (2), a process of preparing an O-alkyl-N-cyanoacetimidate on an industrial scale by reacting an orthoacetic acid trimethyl ester with cyanamide in an alcoholic solution in the presence of an acidic catalyst. 
However, although it is proposed in the preparation process that cyanamide is reacted in an alcoholic solution in the presence of an acidic catalyst, the reaction is carried out under an acidic condition, and thus the material of the reaction vessel should be taken into account and there is the possibility that a usual stainless steel reaction vessel corrodes.
The object of the invention lies in providing, in preparing an O-alkyl-N-cyanoacetimidate, a process of preparing an O-alkyl-N-cyanoacetimidate (hereinafter sometimes abbreviated as CAIM) easily and in a high yield on an industrial scale, without selection of a reaction vessel even by use of an inexpensive iron or stainless steel reaction vessel.
The present inventors have intensely studied for solving the above object, and as a result they found that in preparing an O-alkyl-N-cyanoacetimidate by reaction of an orthoacetic acid ester with cyanamide, the O-alkyl-N-cyanoacetimidate could be prepared easily and in a high yield by making the start of reaction in the presence of an alkaline catalyst, and completed the invention.